Try http://w1.859.telia.com/~u85920178/use/gdo.htm

BR from Ivan

"Tom Coates" wrote in message
...

How do I couple the meter to the antenna?

Tom, N3

Ivan & Tom-

I've had a couple of old Heath GDOs over the years. I was never able to find a
dip by coupling into the antenna's co-ax. I see that Ivan's article above
contains the "secret" method I finally found that works - you have to
short-circuit the feedpoint of the antenna and couple directly to the element.

The article above suggests that you can form a loop in the antenna wire to
couple more tightly to the GDO. However, that would tend to introduce
inductance which would interfere with the measurement. What I do is lay the
coil next to the antenna element so the antenna wire is parallel with the GDO
coil wire tangent.

For example, take a one meter wire or un-bent coat hanger. A GDO coupled to it
should have a dip at 150 MHz. I expect there will also be a dip around 450
MHz, et cetera (odd harmonics).

73, Fred, K4DII